Step 1 Heat the oven to 250 degrees. Halve the loaf of bread crosswise. Pull the bread out in 1- to 1½-inch chunks and put the chunks in a large bowl (save the remaining bread and crusts for another use, such as bread crumbs).
Step 2 In a sauté pan, combine the oil and anchovies over low heat, breaking up the anchovies with the tines of a fork or a wooden spoon, and cooking until the anchovies have disappeared into the oil, about 5 minutes. Stir in the garlic and cook until it is fragrant, about 1 minute (stir constantly so the garlic does not burn). Remove from heat.
Step 3Sprinkle the salt over the bread and drizzle with the seasoned oil. Toss the bread to coat the pieces evenly. Spread the bread in an even layer onto a rimmed baking sheet and bake until golden, about 30 minutes. Check the bread occasionally, using tongs to turn the pieces for even toasting. Remove any smaller croutons that are browning quickly to a plate, until all of the croutons are toasted. Cool the croutons to room temperature before adding to the salad.